QALS-CLIN and QALS-STAT are two independent, but highly coordinated units, which together constitute QALS, a two-stage, phase II, randomized, placebo-controlled, double-blind, multi-center clinical trial of Coenzyme Q10 against placebo (target enrollment 185 patients at 18 clinical sites). The first stage identifies, which of two doses of CoQ10 is preferred (1,000 mg. or 2,000 mg. daily), using a selection procedure to hold the number of patients required to a minimum. The second stage compares the preferred dose against placebo to assess whether there is sufficient evidence of efficacy to justify proceeding to a phase III trial. The primary outcome measure is the change in Amyotrophic Lateral Sclerosis Functional Rating Scale revised (ALSFRSr) score from baseline (randomization) to 9 months, which preliminary research has validated as a surrogate for the gold standard of survival. Four pre-specified secondary supporting hypotheses are also tested. Alternative outcome measures, based on ALSFRSr subscores that may prove more sensitive, will be explored in tertiary analyses as candidates for future trials. The goals of QALS-STAT are: 1) To minimize follow-up-time and number of patients required. 2) To conduct, efficiently integrate, and be responsible for all QALS data management and statistical operations. 3) To transmit to the Clinical Coordinating Center (CCC) in a timely fashion all of the data which the principal investigator of QALS CLIN needs to meet her responsibilities, in terms of ensuring patient safety and directing all clinical operations. Goal 1 is accomplished by the selection procedure, and the use of a surrogate endpoint, which cuts follow-up time by 50%. Goal 2 is achieved by a Statistical Analysis Center, whose personnel have extensive experience in coordination, data management, and programming for clinical trials, as well as their statistical requirements. Goal 3 is ensured by an Operations Committee of QALS-CLIN and QALS-STAT investigators and senior coordinators, which meets frequently under tightly specified and controlled communication protocols.